This invention is concerned with decorative packaging film and, in particular, with a packaging film having a lustrous appearance.
It is well known to manufacture a packaging film having an opalescent pearl-like appearance by forming in the body of the film a large number of microscopic voids. This is achieved, for example in polypropylene film, by incorporating within the film a dispersion of inert particulate material, for example, particulate calcium carbonate having a particle size of about 3 microns, and then stretching the film in one or in two directions at right angles to each other at a temperature below its second order transition temperature when voids are formed at the site of each particle. Such films have wide application in the packaging field, particularly in the packaging of food-stuffs.